ORIGINAL ARTICLE |
https://doi.org/10.5005/jp-journals-10001-1564 |
Utility of Navigation Technology in Functional Endoscopic Sinus Surgery
1-6Department of Otorhinolaryngology, KKR ENT Hospital and Research Institute, Chennai, Tamil Nadu, India
Corresponding Author: Aswathi Paleri, Department of Otorhinolaryngology, KKR ENT Hospital and Research Institute, Chennai, Tamil Nadu, India, Phone: +91 9794228740, e-mail: paleri246cmc@gmail.com
Received on: 03 September 2020; Accepted on: 05 June 2024; Online on: 17 July 2024
ABSTRACT
Objectives: Navigation is a novel technique to aid the surgeon in difficult rhinologic surgeries, such as extensive sinonasal polyposis (SNP), revision surgeries, anatomical variants of the nose and paranasal sinuses, and cerebrospinal fluid leaks. The study aimed to determine the usage of the navigation system for surgeons in functional endoscopic sinus surgery (FESS).
Materials and methods: In this study, 60 patients were recruited from KKR ENT Hospital and Research Institute, Chennai, and divided into groups A and B, who underwent FESS with and without image guidance, respectively. Patients with chronic rhinosinusitis (CRS) with sinonasal polyposis (SNP), undergoing revision surgery for recurrent SNP, sinonasal tumors (SNT), and frontal sinus disease (FSD) were recruited. Lund-Mackay pre- and postoperative endoscopic scores and Sino-Nasal Outcome Test-22 (SNOT-22) scores were analyzed. Computed tomography (CT) scans of the nose and paranasal sinuses were conducted. The patients were subjected to FESS, and following evaluation and affordability, navigation assistance (Fusion Compact Medtronic Navigation System) was used. During the follow-up period, nasal endoscopy was done and postoperative endoscopic scores were calculated along with the SNOT-22 scores.
Results: The pre- and postoperative endoscopic and SNOT-22 values between groups A and B were not significantly different. Intraoperative complications were encountered only in group B, with more recurrences, suggesting a substantial advantage for patients in group A over group B. The correlation between the use of navigation and patient outcomes was significantly different (p < 0.05).
Conclusion: Using the navigation system is an advantage for skilled surgeons to identify the boundaries of anatomical structures with greater accuracy and precision.
How to cite this article: Paleri A, Ramalingam R, Ramalingam KK, et al. Utility of Navigation Technology in Functional Endoscopic Sinus Surgery. Int J Head Neck Surg 2024;15(1):8-13.
Source of support: Nil
Conflict of interest: None
Keywords: Chronic rhinosinusitis, Endoscopic sinus surgery, Sinus polyposis, Surgical navigation.
INTRODUCTION
Chronic rhinosinusitis (CRS) is the inflammation of nasal cavity and paranasal sinuses that lasts for more than 12 weeks, with or without acute exacerbations.1 CRS is considered the most common problem in the field of otorhinolaryngology and it is a highly prevalent inflammatory disease in several countries,2 representing a substantial burden of disease on healthcare, productivity, and the quality of life.3-5 In India, the incidence of CRS is gradually increasing and has significant socioeconomic implications.6-8 Nasal obstruction is the most common symptom in CRS, with nasal discharge, facial congestion, facial pain and hyposmia being the other symptoms.9 Chronic rhinosinusitis is confirmed by nasal endoscopy to assess the extent of sinonasal mucosal inflammation and presence of polyps.10 Topical and systemic steroids are widely used for the treatment of CRS; however, surgery is reserved for patients if the medical treatment fails or is inadequate.11
Chronic rhinosinusitis with nasal polyps is a subset of CRS, where benign outgrowths of sinonasal mucosa, known as nasal polyps, are typically found bilaterally. It is clinically diagnosed based on the presence of objective and subjective evidence of chronic sinonasal inflammation.12 Carcinomas of the nasal cavity and paranasal sinuses account for 3% in head and neck and 0.2–0.8% of all the malignant neoplasms in the body. The tumors originating in the sinonasal cavity may arise either from the lining epithelium or from the underlying bone and cartilage.13 The frontal sinus disease (FSD) is the most common source of intracranial complication in sinusitis, that occurs by hematogenous spread through a communicating venous system.14
Endoscopic sinus surgery (ESS) is one of the most commonly performed surgeries for the treatment of acute or chronic rhinosinusitis, refractory to medical treatment or nasal polyposis.15 Functional endoscopic sinus surgery (FESS) is to remove the obstruction in osteomeatal complex and promote drainage while conserving the normal non-obstructing mucosa and anatomy.16 Even though endoscopes in FESS allow visualization and access to the diseased regions, trauma to the surrounding structures, intraoperative bleeding, and even complications like death can occur.17 There is an inherent risk of major complications occurring in 0.5–1% of such procedures.18 FESS and various anterior skull base surgeries are extremely challenging due to the variety of vascular and neural structures in a very confined space. Moreover, with previous surgical procedures, scarring, and the destructive nature of some diseases, surgical landmarks are distorted, increasing both intraoperative and postoperative complications.19 These complicated situations are made easy with navigation, which aids the surgeon to confirm critical structures.20 Navigation technology may decrease the intraoperative time and greatly reduce the workload of surgeons, with better surgical outcomes.21 Navigation technology may be viewed as a method to improve visualization during surgery and serves as an adjunct to nasal endoscopy.22 The use of image guidance has found to enhance surgeon’s confidence,23 especially while operating cases with altered anatomical landmarks like extensive polyposis or benign or malignant tumors or revision surgery. It is still unclear whether there is a significant drop in intraoperative complications or an improvement in the patient outcome when compared with nonimage-guided surgery.24 With these considerations in mind, this study had been conducted to determine the utility of navigation technology in FESS by comparing the subject with and without image guidance during surgery.
MATERIALS AND METHODS
A total of 60 patients were recruited from June 2017 to June 2019 at KKR ENT Hospital and Research Institute, Chennai. Patients with extensive sinonasal polyposis (SNP), CRS with recurrent nasal polyps after surgery, sinonasal tumors (SNT), and FSD or anatomical variants of the paranasal sinuses were included in this study. Patients with an antrochoanal polyp, mucocele, mycetoma, or dentigerous cyst diagnosed by computed tomography (CT) scan and those under the age of 18 were excluded. All the patients were divided into two groups— group A comprised of 30 patients (14 with SNP, 7 with SNTs, 7 undergoing revision FESS, and 2 with FSD) who were operated on with the aid of navigation. The remaining 30 patients (16 with SNP, 4 with SNTs, 9 undergoing revision FESS, and 1 with FSD) without the assistance of image guidance were classified as group B. Patients who could not afford the expenditure of navigation-aided surgery and those who did not follow-up after the surgery were excluded. A detailed explanation of the availability, cost, and advantage of navigation technology in the current scenario as far as their disease pathology is concerned was given to all the patients. Upon ethical approval from the KKR Institutional Ethics Committee, written consent was obtained from all the subjects.
Sino-Nasal Outcome Test-22 Score
Sino-Nasal Outcome Test-22 (SNOT-22) score is a validated questionnaire for CRS-specific outcome measure consisting of 22 items that capture sinus-specific and general health-related impact of the disease process.25 Factor analysis of the SNOT-22 has revealed that the instrument measures five distinct health domains. The rhinological domain consists of the questions addressing all of the cardinal symptoms of CRS except for facial pain/pressure.
Modified Lund-Mackay Postoperative Endoscopic Score
The Modified Lund-Mackay postoperative endoscopic score (MLMES) is a sinus cavity staging system that scores the endoscopic appearance of the sinus cavities by incorporating polyp, edema, discharge, crusting, and scarring.26 The endoscopic appearance of sinonasal mucosa is graded from zero to six as: 0—normal mucosa, 1—mild edematous mucosa with a patent cavity, 2—severe edematous mucosa with a compromised cavity, 3—mild polypoid mucosa with a patent cavity, 4—severe polypoid mucosa with a compromised cavity, 5—polyp confined within the cavity, and 6—polyp extending beyond the cavity.
Preoperative Assessment
The SNOT-22 questionnaire was provided to all the subjects, and the scores were calculated. All patients underwent clinical examination, radiological, and laboratory investigations. A CT scan of the nose and paranasal sinuses was conducted for all patients in group A according to the navigation protocol specified by the Medtronic Fusion Navigation System. In contrast, patients in group B underwent a regular CT scan of the paranasal sinuses. Pre-intervention nasal endoscopy was performed on both sets of patients, and scores were calculated using the Lund-Mackay endoscopic scoring system. The CT images were then loaded into the computer. The headband, monitor, and emitter were arranged in the Fusion Compact Medtronic navigation system as per the surgeon’s demand. The setup time for the same was calculated and recorded.
Workflow and Setting Up of Navigation System
The patient image data was loaded into the system to analyze the examination details across 80–150 slides of axial, sagittal, and coronal orientation images. The threshold value of 3D images was adjusted to highlight patient anatomy. During the intraoperative period, the patient was intubated, draped, and a sterile head frame with a tracker was attached to the forehead. The tracer registration technique was used, employing bony landmarks on the patient’s face for system confirmation to perform the surgery, with claimed system accuracy of <2 mm.
Surgery
Before the surgery, the surgeon performs an endoscopic examination to confirm the preoperative endoscopic values. FESS in most cases included middle meatal antrostomy, fronto-ethmo-sphenoidotomy, and in cases with SNT, medial maxillectomy with clearance for both groups. During the surgery, the preoperative setup time (only for group A) and intraoperative time were calculated. Additionally, a surgeon’s questionnaire was administered, scoring the ease of operability on various patients, as rated by the surgeon.
Postoperative Outcome
Post surgical reviews were conducted at 4 and 12 weeks. Participants underwent nasal endoscopy, and the SNOT-22 questionnaire was recorded during both visits. Patients post-FESS were advised long-term alkaline and steroid nasal douching along with antihistamines.
Statistical Analysis
Descriptive statistics such as frequency, percentage, mean, and standard deviation were utilized. Pearson’s correlation was employed to establish the relationship between endoscopic score and SNOT-22 score. The Chi-squared test of proportions was used to test for significant differences in baseline demographic variables.
RESULTS
In group A, a total of 20 males and 10 females were recruited, while in group B, there were 19 males and 11 females, resulting in 65% males and 35% females among the subjects. The majority of the subjects were aged above 40 years old (68.33%), with 31.67% being <40 years old. Common symptoms included nasal blockage, the need to blow nose, sneezing, difficulty falling asleep, facial pain, runny nose, and post-nasal drip. Nasal blockage was identified as the predominant problematic symptom encountered in both sets of patients. The SNOT-22 scores were plotted against time to create SNOTgrams. In Figure 1, patients in group A were to have a higher SNOT-22 score before (Fig. 1A) and after 12 weeks (Fig. 1B). Almost 50% in both the groups who were subjected to surgery were diagnosed with chronic rhinosinusitis with polyposis. Additionally, 23% and 30% revision cases in both group A and group B respectively, had recurrent polyposis. Disease extent was measured endoscopically, preoperatively with LMES and postoperatively with MLMES, shown in Table 1. Group A had a mean endoscopic score of 7.90 ± 0.54 preoperatively, marginally higher compared to group B (7.43 ± 0.41). The postoperative 4th-week endoscopic score was notably higher in group A (7.37 ± 1.24), indicating a more extensive FESS with more sinuses opened and thus higher mucosal edema and discharge compared to group B (4.83 ± 0.90). By the end of 3 months, both group A (3.30 ± 1.09) and group B (3.52 ± 1.09) had almost identical mean endoscopic values. There was no statistically significant difference in the endoscopic score and SNOT-22 scores preoperatively and postoperatively at 4 weeks and 12 weeks between the two groups (p > 0.05). There was also no statistically significant improvement in patient outcomes following FESS with navigation assistance compared to nonimage-guided surgery at the end of 12 weeks in both endoscopic and SNOT-22 scores (p > 0.05). However, SNOT-22 scores and endoscopic score over the follow-up period of 12 weeks showed a significant improvement (p < 0.05) in both groups.
| Endoscopic score* | p-value | SNOT-22 score‡ | p-value | Lund-Mackay preoperative endoscopic score | p-value | MLMES | p-value | |
|---|---|---|---|---|---|---|---|---|
| Preoperative | ||||||||
| Group A | 7.90 ± 0.54 | 0.432 | 58.23 ± 4.40 | 0.325 | 7.90 ± 0.54 | 0.432 | – | |
| Group B | 7.43 ± 0.41 | 53.80 ± 3.64 | 7.43 ± 0.41 | |||||
| Postoperative 4th week | ||||||||
| Group A | 7.37 ± 1.24 | 0.175 | 18.80 ± 2.36 | 0.137 | – | 7.37 ± 1.24 | 0.175 | |
| Group B | 4.83 ± 0.90 | 12.90 ± 1.50 | 4.83 ± 0.90 | |||||
| Postoperative 12th week | ||||||||
| Group A | 3.30 ± 1.09 | 0.634 | 13.13 ± 3.14 | 0.667 | – | 3.30 ± 1.09 | 0.634 | |
| Group B | 3.52 ± 1.09 | 11.03 ± 2.07 | 3.52 ± 1.09 | |||||
MLMES, Modified Lund-Mackay postoperative endoscopic score; comparison between mean endoscopic score* and SNOT-22 score‡ in groups A and B, respectively
Figs 1A and B: PSS: Preoperative SNOT-22 Score, PSS 4w: Postoperative SNOT-22 Score at 4 weeks, PSS 12W: Postoperative SNOT-22 Score at 12 weeks in group A (A) in green and group B (B) in blue
By using Pearson correlation coefficient, a significant correlation was established between the preoperative endoscopic score (Fig. 2A) and SNOT-22 score (r—0.363, p—0.004), for postoperative endoscopic (Fig. 2B) at the end of 4 weeks (r—0.758, p—0.0001), 12 weeks (r—0.722, p—0.0001) within the two groups (Fig. 2C).
Figs 2A to C: Correlation between preoperative (A), postoperative endoscopic score and SNOT-22 score at 4 (B) and 12 (C) weeks in both groups
The mean preoperative SNOT-22 score was higher in group A (Fig. 3A) specifically in revision FESS and FSD than group B (Fig. 3B). After the surgical intervention, group A had managed to attain similar mean SNOT-22 score like in group B suggesting greater clearance of disease with the aid of image-guidance. There were no intraoperative complications in group A is an advantage of over group B. The intraoperative time consumption for group A (Fig. 4A) had progressively reduced with a mean of 85 minutes for surgery compared to 101 minutes for group B (Fig. 4B). When comparing the ease of surgery score as per the operating surgeon, significant difference (p < 0.01) was observed between the groups.
Figs 3A and B: Graphical representation and comparison between endoscopic scores and SNOT-22 scores, in group A and group B; ES, endoscopic score; FSD, frontal sinus disease; SNP, sinonasal polyposis; SNT, sinonasal tumor; SS, SNOT-22 score
Figs 4A and B: Operative time of FESS using the navigation in group A (A) and without navigation in group B (B)
After the postoperative period, patients were followed up for 12 months. Recurrences of pathology included one left SNT (25%), one revision (25%), and two SNP (50%) in group A, compared to two SNP (40%), one revision (20%), and two SNT (40%) in group B. During the follow-up period, SNP recurrence was noted in two patients in each group, while there was one case of SNT and one revision FESS in group A compared to two cases of each in group B. No FSD recurrence occurred in either group. Out of the total recurrences in group A, two patients who underwent primary FESS for underlying CRS with nasal polyps were managed medically with a short course of oral steroids and long-term steroid nasal douching. Additional surgery was considered for patients with a history of revision FESS and a diagnosis of a rare SNT, which was performed 1 year after the initial surgery.
In group B, among the recurrences encountered in patients with SNT, one had an undifferentiated squamous cell carcinoma (SCC) originating in the sphenoid sinus, and the other patient had a neuroendocrine tumor. The patient with undifferentiated SCC underwent surgery approximately 8 months after the first surgery, while the other patient was lost to follow-up after 3 months. The recurrences in cases of SNP and revision FESS were managed medically. Therefore, 2 patients (6.67%) from both groups underwent revision surgery.
DISCUSSION
Patients with labyrinthine paranasal sinus orientation, compounded by extensive disease, bone erosion in cases of SNT, or difficult access as in FSD, benefit significantly from image guidance in ESS.27 In our study, the Medtronic Fusion navigation system was used for FESS, offering advantages over nonimage-guided procedures in terms of time efficiency, less invasiveness, accuracy, precision, real-time 3D visualization, increased surgeon confidence during deeper sinus and skull base exploration, and minimal patient discomfort.
In this study, 39 (65%) were males and 21 (35%) were females, consistent with findings from a study by Bagul,28 which indicated that paranasal pathologies are more common in males (62%) compared to females (33%). The outcomes of the patients were measured between and within groups using the SNOT-22 questionnaire and MLMES scores. The SNOT-22 is a reliable and validated tool for assessing quality of life in patients with sinus diseases during both preoperative and postoperative periods.29,30 The comparison of SNOT-22 scores can be presented graphically as SNOTgrams, which display patient symptoms through scores both preoperatively and postoperatively, as well as any exacerbations over time. In this study, the mean SNOT-22 scores between the two groups did not show notable differences over 3 months. However, a significant reduction in overall SNOT-22 scores was observed in both groups following FESS. This is consistent with several studies demonstrating a statistically significant improvement in quality of life, as measured by SNOT-22, following ESS, irrespective of whether navigation was used or not.25,31,32 The MLMES is a sinus cavity scoring system that scores the inflammatory burden of sinus cavities post ESS has great inter- and intraobserver variability.33 In the present study, MLMES scores correlated well with the subjective SNOT-22 scores, but using the image-guidance did not change the patient’s outcome both subjectively as well as objectively (p > 0.05) as seen in the other studies too.26
The present study gathered enough evidence that, over time, as the familiarity between the system and the operating surgeon increases, the preoperative setup time reduces. The setup time over 2 years improved from 15–35 to 10–15 minutes, which is strikingly similar to the study conducted by Al-Swaiahb and Al-Dousary, with a Landmark X system.34 In another study, similar outcomes were deduced, where the preoperative setup time typically reduced to 5–15 minutes.35 The surgeon’s questionnaire scores provided light on the fact that in the hands of an experienced surgeon image guidance helps identifying altered anatomy due to extensive disease or previous surgery. However, this can lead to overconfidence and the surgeon over-estimating the surgical skills. Similarly, accuracy and technical errors in image generation can also lead to an unforeseen complications. There were two intraoperative complications, an anterior ethmoidal artery bleed in revision surgery and the other, a cerebrospinal fluid leak with a right-sided SNT; however, later it was confirmed as undifferentiated SCC by biopsy report in group B and none in group A. The results of the intraoperative incidence of complications was very similar to a retrospective comparative study conducted34 and further supported by studies conducted by Olson and Citardi36 and Fried et al.37 A regular follow-up of the patients at timely intervals for early detection of recurrence is strongly recommended.
In this study, group A had only one major complication (orbital entry) and group B had seven major complications. This suggests that navigation helps minimize the complications associated with ESS, even though the number of patients were not proportionately enough to demonstrate the outcomes, and hence, it’s statistically insignificant (p > 0.05). Mostly, the patients with CRS who had complications associated with ESS also experienced these issues in other populations.26 In our study, there were four cases (13.33%) of recurrence in group A compared to five (16.67%) in group B. Additional surgery was advised for a patient each in both groups. The present study showed there was no statistically significant benefit of navigation over image-guidance assisted group. A similar result was put forward in a few other populations as well, in terms of revision surgeries.38,39 Even though there was no difference in patient outcomes, the surgeon’s confidence in approaching the difficult cases were markedly above when accompanied with image-guidance.23 Especially in the hands of a trained surgeon well-versed in anatomical aspects, the likelihood of significant intraoperative complications was markedly reduced.37,40
The present study must be interpreted within the context of its limitations. The small study population constrained various statistical outcomes. However, in summary, navigation technology has enabled surgeons to approach surgically challenging cases with minimal perioperative morbidity. Effective use of navigation systems requires proper training in setup and extensive surgical experience. Despite the benefits of navigation systems, surgeons also need advanced surgical proficiency and a deeper understanding of anatomical nuances in the surgical field. Nevertheless, image-guided surgery should be offered as an option to patients, dealing with intricate cases of paranasal pathology.
CONCLUSION
Navigation technology tends to increase the surgeon’s confidence in operating on challenging cases and reduces surgical morbidity. Thus, the image-guided navigation system has proven valuable in enhancing and complementing the knowledge and skill of surgeons.
ETHICAL APPROVAL
Ethical clearance was given by ethical committee of the Institutional Review Board.
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